부산대학교 도서관

Fluctuation relations allow for the computation of equilibrium properties,like free energy, from an ensemble of non-equilibrium dynamics simulations.Computing them for quantum systems, however, can be difficult, as performingdynamic simulations of such systems is exponentially hard on classicalcomputers. Quantum computers can alleviate this hurdle, as they can efficientlysimulate quantum systems. Here, we present an algorithm utilizing a fluctuationrelation known as the Jarzynski equality to approximate free energy differencesof quantum systems on a quantum computer. We discuss under which conditions ourapproximation becomes exact, and under which conditions it serves as a strictupper bound. Furthermore, we successfully demonstrate a proof-of-concept of ouralgorithm using the transverse field Ising model on a real quantum processor.The free energy is a central thermodynamic property that allows one to computevirtually any equilibrium property of a physical system. Thus, as quantumhardware continues to improve, our algorithm may serve as a valuable tool in awide range of applications including the construction of phase diagrams,prediction of transport properties and reaction constants, and computer-aideddrug design in the future.